[SOLVED] Can I name a JavaScript function and execute it immediately?

Issue

I have quite a few of these:

function addEventsAndStuff() {
  // bla bla
}
addEventsAndStuff();

function sendStuffToServer() {
  // send stuff
  // get HTML in response
  // replace DOM
  // add events:
  addEventsAndStuff();
}

Re-adding the events is necessary because the DOM has changed, so previously attached events are gone. Since they have to be attached initially as well (duh), they’re in a nice function to be DRY.

There’s nothing wrong with this set up (or is there?), but can I smooth it a little bit? I’d like to create the addEventsAndStuff() function and immediately call it, so it doesn’t look so amateuristic.

Both following respond with a syntax error:

function addEventsAndStuff() {
  alert('oele');
}();

(function addEventsAndStuff() {
  alert('oele');
})();

Any takers?

Solution

There’s nothing wrong with the example you posted in your question.. The other way of doing it may look odd, but:

var addEventsAndStuff;
(addEventsAndStuff = function(){
    // add events, and ... stuff
})();

There are two ways to define a function in JavaScript. A function declaration:

function foo(){ ... }

and a function expression, which is any way of defining a function other than the above:

var foo = function(){};
(function(){})();
var foo = {bar : function(){}};

…etc

function expressions can be named, but their name is not propagated to the containing scope. Meaning this code is valid:

(function foo(){
   foo(); // recursion for some reason
}());

but this isn’t:

(function foo(){
    ...
}());
foo(); // foo does not exist

So in order to name your function and immediately call it, you need to define a local variable, assign your function to it as an expression, then call it.

Answered By – Mark

Answer Checked By – Clifford M. (BugsFixing Volunteer)

Leave a Reply

Your email address will not be published.